The First Sounds
For the first few weeks, the family only heard the strange sounds here and there. As each member of the household heard it alone, they brushed it off as part of the way the house was built. Perhaps a more unified approach would have been taken had multiple members heard it simultaneously.

The First Sounds
This is exactly what happened a short time later, when family gatherings started to be interrupted with the strange noise coming from the walls. It started to happen more frequently, so everybody knew that they had to do what they could to get to the bottom of the mystery.
